I. Field of the Invention
The present invention relates to an apparatus for removing the contents of pressure vessels with inoperative or damaged valves.
II. Background Information
Pressure vessels are commonly used to store volatile hazardous materials. Should access through valves become impractical, the contents cannot be accessed through ordinary means.
Conventionally, such access has been obtained by supporting a new main valve adjacent the vessel wall or adjacent an existing product line to the vessel. A drilling mechanism is attached to the main valve and a drill bit is accessible through the opened main valve to pierce the walls of the container and/or product line. The drill bit may then be removed from the main valve, the main valve closed, and an eductor tube connected to the main valve in place of the drilling mechanism. The main valve may then be reopened to permit discharge of the contents of the vessel through the eductor tubing.
In known prior art tapping assemblies, should the drill bit become damaged and require replacement, the drilling mechanism must be removed from the main valve. This removal process may prove difficult and time consuming. In addition, with known tapping assemblies, some of the contents of the vessel being tapped may be captured between the main valve and the drilling mechanism and released to the atmosphere upon removal of the drilling mechanism to replace a damaged drill bit.
In addition, with known tapping assemblies it may be difficult or impossible to remove some or all of the content of the vessel being tapped without first removing the drilling mechanism from the main valve. Accordingly, with such prior art tapping assemblies, it is not feasible to readily sample the contents of the tapped vessel after piercing and prior to removal of the drilling assembly.
It is, accordingly, an object of the present invention to provide an improved tapping assembly which permits easy and safe replacement of drill bits.
Another object of the present invention is to readily allow sampling of the contents of a vessel being tapped prior to removal of the drilling assembly.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention.